Could you point me to something I could study to make a design change so I would get some volume? It really only needs to be as loud as a cell phone's speaker volume for practice purposes.
Thank you in advance for any help,
yeto
You need to stick a small power amplifier between the output and the speaker - something like an LM386 should do.
Or get one of these:
Peavey :: AmpKit LiNK II
And actually play THROUGH your smart phone. The thing includes emulated popular effect pedals right in it.
They also make a USB interface so you could play through your lap top or whatever.
Peavey :: XPort USB Guitar Interface
Peavey :: AmpKit LiNK II
And actually play THROUGH your smart phone. The thing includes emulated popular effect pedals right in it.
They also make a USB interface so you could play through your lap top or whatever.
Peavey :: XPort USB Guitar Interface
No, it has almost ZERO current capability so it will not drive any speaker, but as suggested above:
For the full project, go to GGG
Use it *without* the gain boost (you save a switch and a cap )
I want to build a small practice amp. It doesn't have to be any louder than a cell phone. I am new at this but if I understand correctly JFETs sound more like tubes versus Op-amps. That is why I don't want to use the LM386. Can I use anything from the following link to accomplish my goal? Also, would a different JFET other than the J201 power a small/tiny speaker?
https://www.google.com/url?q=https:...sntz=1&usg=AFQjCNFZuOyl36AcvOmme76U2-MgEH-zCQ
Thanks in advance for any help,
yeto
https://www.google.com/url?q=https:...sntz=1&usg=AFQjCNFZuOyl36AcvOmme76U2-MgEH-zCQ
Thanks in advance for any help,
yeto
JFET's are poorer quality, similar to valves - but the JFET's in the preamp will give you the distortion and lower quality you appear to be wanting.
The LM386 will merely amplify that 'poorer' quality in order to feed a speaker.
For a practice amp, particularly such a tiny one, I don't see as you'd be able tell if it was FET, valve, or transistor. What makes the most difference is playing skill, not what amp you're using.
You can certainly build FET power amplifiers, but they aren't going to sound like valves.
Hi,
Your overcomplicating something very simple.
Follow the good advice you have been given.
Use the LM386.
Anything more complicated will really kill battery life.
(Like any type of class A type speaker output.)
Keep the normal pedal output, (wired also to the amp).
Add a 1/4" speaker out but use a stereo socket that
with a mono plug connects the power to the chip
when the speaker plug is inserted.
How loud 1/2 watt goes depends on the speaker connected.
rgds, sreten.
I really like the sound of the provided sound clips of this amp...
The Bulbamp: 1 Watt guitar class A amplifier with a light bulb
...but from my research on the internet people say it is hard to bias and I am thinking this might be too complicated for my first build. While I am in the learning process I was hoping to "sort of" do the same thing with JFETs. Do you think this might be possible?
Thanks,
yeto
The Bulbamp: 1 Watt guitar class A amplifier with a light bulb
...but from my research on the internet people say it is hard to bias and I am thinking this might be too complicated for my first build. While I am in the learning process I was hoping to "sort of" do the same thing with JFETs. Do you think this might be possible?
Thanks,
yeto
I'd visit a pawn shop, you could get a good deal on an actual practice amp cheaper than it would cost to build one. A couple of years ago I saw a Fender Champ amp for $25, I was tempted to buy it even though I don't play anymore.
Mike
Mike
When you are talking cell phone volumes, even a tube amp won't sound much like a tube amp. Your ears do not hear the same at quiet levels as they do at louder levels. There won't be much acoustic interaction between the strings and the speaker. A lot of tubbiness in a tube output stage happens as the level get near the maximums. You only get that at loud. Your preamp is going to create a much larger portion of your tone than the power amp in this application. And the speaker will have the greatest contribution of all.
I suggest you try reading all the replies you've had, and stop asking the same question over and over 😀
So, just so I understand it is not possible, by just using JFETs, to build an amp that will power a small speaker? I have searched on the internet and I see plenty of schematics for preamps but not amps. A preamp amplifies the signal somewhat. Why can't the signal be amplified enough to drive a speaker?
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Hi,
You asked about modifying a presumably battery powered effects pedal
to drive a loudspeaker. You have been told how to sensibly simply do it.
Yet you persist on enquiring about poor battery draining options.
rgds, sreten.
You asked about modifying a presumably battery powered effects pedal
to drive a loudspeaker. You have been told how to sensibly simply do it.
Yet you persist on enquiring about poor battery draining options.
rgds, sreten.
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That's what the LM386 is doing - amplifying the existing JFET signal to feed a speaker. Why would you imagine a JFET solution (which doesn't exist) would sound any better.
Perhaps you would better understand a 'real world' example?.
Your JFET is a roller skate - you're asking us if your roller skate can be used to transport a full shipping container, we've told you "no, you need a truck".
That's why you can't find solutions on the Internet.
I guess what I can't understand is that the LM386 is just some diodes, transistors, and resistors in one package. Why can't the same be done but the components be separate?
Take the "Ruby" schematic for instance.
Ruby
Why can't the individual components inside the LM386 be separated out instead of using the LM386?
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